PCIe SSD as cache drive...

anti-clockwize · January 13, 2015

Hullo.

Just curious,

What do people think about the possible benefits of using something like the GSkill Phoenix Blade as a cache drive.

Ignore the fact that it has far more capacity than what is needed for cache.

Ignore the cost.

If you were running, say, a 850 PRO 500 GB, with 8-16GB RAM with a decent processor, would a PCIe SSD (whether it be an M.2 adapter with a single M.2 SSD or a PCIe SSD with sf-2281 raid0) with it's slightly higher access time and super high sequential reads (1500MB/s - 2000MB/s) used as a cache drive show some benefit for heavy daily usage (anything short of 4k video editing and high rate server access)?

...

What about if you were running 32GB of RAM with 50-75% dedicated to a RAMdisk, could the PCIe SSD show more benefit then?

Is there away to Optimize a RAMdisk using a PCIe SSD?

With RAMdisks, the contents must be dumped to a drive during start up and shut down. Could the fast sequential reads and writes of a PCIe SSD show some benefits in these scenarios, allowing quicker dumping of the RAMdisk to get on with other things?

Has anyone got any real-life experience with setups similar to this that could comment? Otherwise, does anyone care to speculate ?

Cheers guys.

MiniMoose1211 · January 13, 2015

I know my motherboard has a function to run an m. 2 ssd as a cache and some people use it. But if you're going to use a pcie ssd, you might as well just use it as a boot drive instead of caching.

TheGeekster · January 13, 2015

I honestly doubt you'd see much of a difference between an SSD and a SSD with a pcie SSD as a cache.Would just seem to use more resources bothering to cache anything.

As per the RAM disk, you may see some accelerated startup and shutdown of the disk, but the cost to performance gains, really wouldn't be worth it. I'd imagine with a pcie ssd you could just use that as the storage for what ever is necessary. My cheapish crucial MX100 has sequential write speed of 450MB/s, with a 16GB RAMDISK, it would take 36 seconds to write the entire thing to disk, which, for a 16GB RAMDISK is pretty damn good, a more standard 4GB RAMDISK would only take 10 seconds.

wpirobotbuilder · January 13, 2015

Very little benefit unless you do have an incredibly high cache hit rate and need lots of throughput. If you already have an SSD boot drive it's not going to give you much benefit -- better to use it as a boot drive.

If you used it as a datastore for something like ESXi then it would be much better utilized.